<title>Current Mirror</title>
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<applet code=Circuit.class archive=circuit.jar width=640 height=450>
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<param name=pause value=20>
<param name=startCircuit value="mosmirror.txt">
<param name=startLabel   value="Current Mirror">
<param name=useFrame     value="false">
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<p>
This is a <a href="http://en.wikipedia.org/wiki/Current_mirror">current mirror</a>,
a device that uses the current in one half of the circuit to control the current
flow in the other half.  The current is the same in both halves.  The switch on
the left changes the current flow in the left half, which is mirrored in the
right half.  The switch on the right causes the resistor to be bypassed, but the
current mirror ensures that the flow of current does not change.
<p>
If the left <a href="http://en.wikipedia.org/wiki/MOSFET">MOSFET</a> is in saturation mode, its current is determined only by the
gate-source voltage.  The left MOSFET has its gate and drain tied together, so
the drain voltage determins the current.  The right MOSFET has the same gate-source
voltage, so the current must be the same, as long as it is in saturation mode.

<p>
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<br>Generated Tue Dec  7 2010
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